Hans christofferson



H. CHRISTOPFERSON. STEAM ENGINE. No. 458,943. Patented Sept. 1

(No Model.)

.E el ew 51%@ NITED STATESl PATENT OFFICE.

lIANS CHRISTOFFERSON, OF HUDSON, VISOONSIN, ASSIGNOR OF FIFTY-ONE ONE-HUNDREDTl-IS TO HARRY L. NORTl-I AND CLINTON FULTON, OF SAME PLACE.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 458,943, dated September 1, 1891.

Application filed February '7, 1891. Serial No. 380,641. (No model.)

To all whom t may concern: tersinks or channels Il for the insertion of Be it known that I, HANS OHRISTOFFERSON, set screws or bolts Il, which are threaded in a citizen of the United States, residing` at the piston-head and ilnpinge the hollow pis- Hudson, in the county of St. Croix and State ton-rod G at their inner ends, thus securing of /Visconsin, have invented certain newand the said rod and pistons firmly together. Lo- 55 useful Improvements in Steam-Engines, of cated between these outer piston-heads i 5 is which the following is a full, clear, and exact another piston-head l2, having, like the forspecitication, reference being had to the acmer, packingrings 10, held in place bymeans coinpanying drawings, which form a part of of removable plates 7, as before described io this specification. with reference to the headsl 5. This inner 6o My invention relates to means for relieving piston-head is provided with a neck or hub the bed of the engine from the back-pressure lil, through which the hollow piston-rod 6 reoccasioned by the force exerted between the yciprocates. Fitted snugly within the hollow cylinder and crank-shaft in ordinary7 engines piston-rod 6 is another, but preferably solid,

and applying such pressure directly to the piston-rod la, and to thisinner rod thepiston- 65 crank-shaft, whereby the damage usually enhead l is secured by means of a number of tailed by the excessive strain exerted on the (preferably four) keys l5. These keys are bed and other connecting parts will be endriven through tapering holes in the hub 1S tirely avoided; and my invention consists in and enter corresponding holes in the rod Il 2o certain features of novelty hereinafter fully and preferably pass entirely through the said 7o described in connection with the drawings, rod and also through the other side of the and particularly pointed out in the claims. hub. Inasmuch as the head l2 moves inde- Referring now to the said drawings, in pendently of the hea-ds t 5, it is necessary to which like signs of reference indicate like provide the hollow rod G with longitudinal parts throughout the several views, Figure I slots I6, through which the ends of the keys 75 is a plan view of my improved engine partly pass and along which said keys slide as the in section. Fig. Il is an enlarged longitudipiston l2 and rod G move relatively t0 each nal section of the cylinder-pistons and their other, the length of the slots IG being of rods. Fig. III is a detail view of one of the course equal to the extent of the travel of the 3o outer piston-heads, showing the mannerof sehead l2 relatively to the rod G. Se curing the saine to its rod. Fig. IV is a de- The crank-shaft 2,itwillbe seen, is provided tail sectional view taken on the line IV IV, with preferably three cranks, one of which Fig. II. Fig. V is a transverse sectional View stands in an opposite direction to the others; of the pistou-rods and packing-ring hereinbut it will of course be understood that but after described, taken on the line V V, Fig. II. two cranks would answer the same purpose. S5

In carrying out my invention I employ a I prefer to use three, however, as by so doing bed 1, of any suitable construction, in one the strain on the innercroSs-head is balanced end of which the crank-shaft 2 is suitably and the tendency to bind in its guideway and journalcd and upon the other end of which bend the piston-rod is avoided. The inner 4o the open-ended cylinder 3 is mounted. rlhe crank is connected by means ot pitxnan 17 to 9o cylinder 3,insteadof being provided with the a cross-head 1S,andthis cross-head is secured usual fixed heads, is provided with two inovto the inner piston -rod Il. The two outer able piston-heads l 5, secured to ahollow piscranks are connected by means of pitmen 19 ton-rod G and having a fixed relation to each tothe outer ends of a cross-head 20, which latother. These piston-heads are each provided ter is suitably securel to the hollow piston- 95 with removable plates 7, seated in sockets S rod G. and secured therein by means of bolts 9 for The inner piston-head .l2 may be provided the purpose of holding the piston packingon one or both sides withasuitable pack-nut rings 10 in place. The sockets 8 orany suit- 2l for forcing the packing 22 against the keys 5o able number ol them are provided with counl5 and into the grooves l, so as to avoid the roo escape of steam between the head and rod. Interposed between the nut 21 and packing 22 is a ring 21, having lugs 2lb' projecting into the grooves 1G for holding the packing in said grooves, the said ring being divided into four sections, as shown in Fig. V, to facilitate its insertion. Both ends of the hollow rod may also be provided withstuiing-boxes 23, of any suitable construction, for guarding agtinst the escape of steam between the two ro s.

From the foregoing description it will be seen that steam entering the cylinderbetween the inner piston-head and one of the outer heads 4 5 will force the two heads in opposite directions, causing the piston-rods to reciprocate in opposite directions, and thus applying the back-pressure which would otherwise be sustained by lthe steam-cylinder directly to the crank-shaft.

Having thus described my invention, What I desire to secure by Letters Patent 11s- 1. In an engine, the combination, with the cylinder, of the outer piston-heads, the inner piston-head located between said outer heads, a hollow piston-rod passing through said inner head and being secured to said outer heads, the inner piston-rod located in said hollow rod and being secured to the inner piston-head, the packing', and the packing-ring having lugs holding said packing in the slots of the said hollow rod, substantially as set forth.

v 2. In an engine, the combination, with the cylinder, of the pis-tons 4 5, a hollow slotted rod 6, to which said pistons are secured, lthe rod 14 Within said hollow rod, the piston I2 between the pistons 4 5, keys passing through the slot-s of the rods G and securing the piston l2 to the -rod 14, the packing located in the slots of the said rod 6, and the packingring held against said packing, substantially as set forth.

3. In an engine, the combination, with the cylinder, of the pistons 4 5, a hollow slotted rod 6, to which said pistons are securedthe rod 14, fitting in the rod 6, the pistoni?, located between the pistons 4 5, loose on the rod 6, and having a hub, keys passing through said hub and slots of the rod 6 and securing said piston I2 and rod 14 together, packing arranged in the slots of said rod 6 against said keys, the lugs 2lb, arranged against said packing, and a pack-nut impinging said lugs, substantially as set forth.

HANS CI-IRISTOFFERSON.

lVitnesses:

J oHN W. BAsHFoRD, CHARLES A. DEsULY. 

